Reservoir lost 27.8m acre-feet of groundwater in 20 years, Nasa study finds, vanishing ‘twice as fast as surface water’

The Colorado River basin has lost 27.8m acre-feet of groundwater in the past 20 years, an amount of water nearly equivalent to the full capacity of Lake Mead, the largest reservoir in the United States, a new study has found.

The research findings, based on Nasa satellite imagery from across the south-west, highlight the scale of the ongoing water crisis in the region, as both groundwater and surface water are being severely depleted.

“Groundwater is disappearing 2.4 times faster than the surface water,” said Jay Famiglietti, a hydrologist at Arizona State University and the study’s senior author.

“Everyone in the US should be worried about it, because we grow a lot of food in the Colorado River basin, and that’s food that’s used all over the entire country,” he added. “These days, we’re also supporting a number of data centers and computer chip manufacturers, and these are essential to our economy.”